
let isDone:boolean = false;
let count:number = 88;
let names:string = 'liuyu';
let u:undefined;
let n:null;

let list:number[] = [1,2,3];

enum Direction { // 枚举
    NORTH,
    SOUTH,
    EAST,
    WEST
}
let dir:Direction = Direction.NORTH;

let notSure:any = 9999; // any 为任何类型
notSure = 'good';

let value:unknown;

let tupleType:[string,boolean]; // 元组
tupleType = ['isNB',true];

function warnUser():void { // 函数返回值为空

}



